It was interesting to see other reviews call this "more interesting than dry history lessons". As an A level history student, I have to disagree with that view, because history is the best subject in the world, but it has a good point.
This book is, like the TV series, broken down into exciting and intriguing little episodes of the first half of the 20th century. Although the book lacks real detail and fluency, the personal nature of the tiny chapters makes them more 'real' and interesting. The big downside for me was Marr's sweeping authoritative generalisations, which are so common you get used to them. There is, to this reader, a lot of simplification. But if you accept that this is a casual story being told by a journalist and not a historian, you can get into it. As well as all the key British events of the early 20th century which (if you're anything like me!) you feel you should know about, the book also has some more unusual tales, such as that of the mad Mitford sisters. There were a few bits on literature and architecture which I skipped, but the majority of the book was very enjoyable. In particular, the fascinating personalities of David Lloyd George and Winston Churchill came across more than they would have done if they were mere characters in a proper history book.